Liquid crystal display and manufacturing method thereof

ABSTRACT

In an LCD, according to an embodiment of the present invention, a projection  6  is structured on top of insulation layer  8  on a TFT glass substrate  10  and under part of a black matrix  9.  The projection  6  encircles the transparent region in each pixel so that a spacer  17  cannot climb over the projection  6  and enter the transparent region even though a certain pressure is applied onto the substrates  10  and  11.  The width of the projection  6  is equal to or less than the diameter of the spacer  17.  The height of the projection  6  is equal to or longer than approximately 1% the length of the diameter of the spacer  17,  and it is preferable that it be equal to or longer than approximately 2%.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a liquid crystal display (LCD)and its manufacturing method.

[0003] 2. Description of the Related Art

[0004] The TN (twisted nematic) mode is one of the current modes usedfor LCD devices. In this mode, an electric field vertical to the surfaceof the substrate is used to orient the liquid crystal molecule director(the molecular major axis). By doing this, the optical transmittance iscontrolled so that an image can be displayed on the LCD panel. This is acommon type (hereafter called a vertical electric field driver-type) ofLCD device.

[0005] Since, with the vertical electric field driver-type LCD, thedirector is oriented to be vertical to the surface of the substrate whenthe electric field is applied, the refractive index changes depending onthe viewing angle. Accordingly, the vertical electric field driver-typeLCD is not suitable when a wide viewing angle is needed.

[0006] There are also LCD devices where the liquid crystal director isoriented parallel to the surface of the substrate. These are deviceswhere the electric field functions in a direction parallel to thesurface of the substrate so that the director can rotate in a planeparallel to the surface of the substrate. Through this, the opticaltransmittance is controlled, and an image is displayed. This type(hereafter called a lateral electric field driver-type) of LCD devicehas only just been developed in recent years. With the lateral electricfield driver-type LCD, because the change in refractive index due to theviewing angle is remarkably small, a high quality display can beobtained.

[0007] An example of this type of lateral electric field driver-type LCDis shown in FIGS. 1 to 3. FIG. 1 is a plan view of a vertical electricfield driver-type LCD, FIG. 2 is a cross-sectional view of the LCD inFIG. 1 taken along the line JJ′, and FIG. 3 is a cross-sectional view ofthe LCD in FIG. 1 taken along the line KK′. The pixel shown in thesediagrams is formed of the following elements: a data line 1, a scanningline 2, a thin film transistor (TFT) 3, a common electrode 4 and a pixelelectrode 5. The scanning line 2 is connected to an external drivecircuit (not shown in the figures). The TFT 3 is a switching device. Thescanning line 2 and the common electrode 4 are both structured on asubstrate 10 where TFTs are fabricated (hereafter, called TFT substrate10). The pixel electrode 5 and the data line 1 are structured on thescanning line 2 and the common electrode 4 via an interlayer insulationfilm 7. The pixel electrode 5 and the common electrode 4 are alternatelypositioned. These electrodes are covered with a protection/insulationfilm 8. On the protection/insulation film 8, an alignment layer 15 islaid and subjected to a rubbing treatment.

[0008] A black matrix 9 to shield light is structured in a matrix formaton the underside of the opposite facing glass substrate 11. The primaryand secondary colored layers 12 and 13, which are necessary for colordisplay, are prepared on the black matrix 9. Each of the colored layers12 and 13 are assigned to each pixel. Here, the above two colorsrepresent two of the three primary colors: red, green, and blue. But,the one remaining colored layer is not shown in the figures.

[0009] On top of the primary and secondary colored layers 12, 13, anover-coating film 14 necessary to make the opposite facing substrate 11flat is prepared. An alignment layer 16, which will be necessary toorient the liquid crystal 18, is laid on the over-coating film 14 andthen subjected to a rubbing treatment. The rubbing treatment isperformed in the direction opposite to that performed on top surface ofthe TFT substrate 10.

[0010] Next, liquid crystal 18 and spacers 17 are poured into the gapbetween the TFT substrate 10 and the opposite-facing substrate 11. Thespacers 17 are randomly distributed throughout the area between them.The minimum distance between the two substrates determines the diameterof the spacers 17.

[0011] A polarizer film (not shown in the figures) is applied to theouter surface of the TFT substrate 10 where the electrode patterns havenot been formed. This polarizer film is applied in a manner such thatthe transmission axis runs in the direction perpendicular to thedirection of the rubbing. A polarizer film (also not shown in thefigures) is applied to the outer surface of the opposite facing glasssubstrate 11 where there are no layered patterns. The transmission axisof the polarizer film on the opposite facing glass substrate 11 isperpendicular to the direction of the transmission axis of the polarizerfilm on the TFT substrate 10.

[0012] The LCD panel with the above structure is set up on a backlightand attached to a drive circuit.

[0013] In the above mentioned conventional LCD device, the liquidcrystal poured into the narrow gap between the TFT substrate and theopposite facing substrate is normally oriented parallel to the directionthat the rubbing treatment was performed on the alignment layers 15 and16. As shown in FIG. 4, the liquid crystal molecules 20 surrounding eachspacer 17 are oriented parallel to the surface of the spacer 17. In thiscase, when the screen is in normally black mode (i.e. the mode where nolight can pass through when no voltage is applied), light permeatesthrough the area where the liquid crystal molecules are lined up askewto the polarizer film absorption axis (for example, the liquid crystalmolecules in region 21). Due to this, a leakage of light develops in thefan blade-shaped regions 21. In addition, the weak aligning force causesthe alignment of the liquid crystal surrounding the spacers 17 to fallinto disorder. When this happens, the amount of leakage of light aroundthe spacers 17 increases; subsequently, as shown in FIG. 5, adoughnut-shaped region 21 of leakage of light develops.

[0014] Furthermore, when the liquid crystal panel happens to beimpacted, the spacer 17 becomes charged by the friction created frombeing scraped against the alignment layers on the TFT substrate and theopposite facing substrate respectively. Once this occurs, a radialelectric field develops around the spacers 17. In this case, because theliquid crystal molecules 20 become aligned parallel to the electricfield, fan blade-shaped regions 21 of leakage of light develop, as shownin FIG. 6.

[0015] At this point, when comparing the two cases where the spacer 17is not charged as shown in FIG. 4 and where the spacer 17 has beencharged up as shown in FIG. 6, it is apparent that the latter case giveslarger radial areas of leakage of light 21.

[0016] This type of charging occurs when a certain pressure or impact,which happens to hit the LCD panel, causes spacers that are positionedin the opaque region of liquid crystal molecules (i.e., in the region ofcrystal molecules under the black matrix) to move and be strongly rubbedby the top surfaces of the alignment layers. This occurs easily sincethe gap at the opaque region (i.e., the region under the black matrix 9and on the data line 1, the scanning line 2, the TFT 3, etc.) isnarrower than the gap at the transparent regions, which widens thecontact area of the spacer with either surface of the alignment layers.The wider contact area allows a conveyance of a strong force, which iscaused by the certain pressure or impact being applied to the LCD panel,onto the spacer. This force can easily push and move the spacer out intoa transparent region of liquid crystal molecules. An electricallycharged spacer that has entered the transparent region increases thetotal amount of leakage of light, which in turn causes a deteriorationof display quality. On the other hand, a spacer that is originallypositioned within the transparent region of liquid crystal molecules israrely charged electrically by this type of movement since the gap ofthe transparent region is wider.

[0017] As described above, when a certain pressure or impact is appliedto the LCD panel, the spacer that is positioned within an opaque regioncan easily migrate to a transparent region and, especially when the LCDshows at all display area, an increase in leakage of light 21 becomesnoticeable. Besides, when the distribution of the spacers 17 is notuniform, the display quality becomes distorted and a problem developswhere the contrast decreases due to the leakage of light.

SUMMARY OF THE INVENTION

[0018] The present invention has been developed taking the aboveproblems into consideration, comprising an active matrix LCD device andits manufacturing method, which have been made so that the amount ofleakage of light is reduced and the degradation of display quality isprevented to avoid spacer's moving into a transparent region when thedevice is shaken or impacted.

[0019] According to an aspect of the present invention, an LCD with atleast one spacer (17) supporting two substrates that face each other isprovided and is comprised of at least one spacer (17) which ispositioned under an opaque region (9), and at least one projection (6,19) which is formed under the said opaque region (9), and on at leastone of the inner-most surfaces of a first and a second substrate. Anexample of the LCD is illustrated in FIG. 7.

[0020] According to an aspect of the present invention, an LCD with atleast one spacer (17) supporting two substrates that face each other isprovided and is comprised of at least one spacer (17) which ispositioned under an opaque region (9), and a broken line of projections(6, 19) which are formed on at least one of the inner-most surfaces of afirst and a second substrate so as to encircle a transparent region.

[0021] According to an aspect of the present invention, a method ofmanufacturing an LCD is provided and is comprised of the following stepsof depositing an insulation film (8) on a transparent substrate (10,11); etching off an area of the said insulation film 8 under an opaqueregion so as to form a ditch; and depositing an alignment layer (15) onthe resultant surface of the said insulating film (8). An example of themethod is illustrated in FIGS. 20 and 21.

BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and other objects, features and advantages of thepresent invention will become more apparent from the following detaileddescription, when taken in conjunction with the accompanying drawings,wherein:

[0023]FIG. 1 illustrates a plan view of a conventional lateral electricfield-type LCD;

[0024]FIG. 2 illustrates a cross-sectional view of the conventional LCDtaken along a line JJ′ in FIG. 1;

[0025]FIG. 3 illustrates a cross-sectional view of the conventional LCDtaken along a line KK′ in FIG. 1;

[0026]FIG. 4 illustrates an enlarged schematic plan view of liquidcrystal molecules around the spacer in FIGS. 2 and 3;

[0027]FIG. 5 illustrates an enlarged schematic plan view of liquidcrystal molecules around the spacer in FIGS. 2 and 3;

[0028]FIG. 6 illustrates an enlarged schematic plan view of liquidcrystal molecules around the spacer in FIGS. 2 and 3;

[0029]FIG. 7 illustrates a plan view of an LCD, according to the firstembodiment of the present invention;

[0030]FIG. 8 illustrates a cross-sectional view of the LCD taken along aline AA′ in FIG. 7;

[0031]FIG. 9 illustrates a cross-sectional view of the LCD taken along aline BB′ in FIG. 7;

[0032]FIG. 10 illustrates a plan view of an LCD, according to the secondembodiment of the present invention;

[0033]FIG. 11 illustrates a cross-sectional view of the LCD taken alonga line CC′ in FIG. 10;

[0034]FIG. 12 illustrates a cross-sectional view of the LCD taken alonga line DD′ in FIG. 10;

[0035]FIG. 13 illustrates a plan view of an LCD, according to the thirdembodiment of the present invention;

[0036]FIG. 14 illustrates a cross-sectional view of the LCD taken alonga line EE′ in FIG. 13;

[0037]FIG. 15 illustrates a cross-sectional view of the LCD taken alonga line FF′ in FIG. 13;

[0038]FIG. 16 illustrates a plan view of an LCD, according to the fourthembodiment of the present invention;

[0039]FIG. 17 illustrates a cross-sectional view of the LCD taken alonga line GG′ in FIG. 16;

[0040]FIG. 18 illustrates a cross-sectional view of the LCD taken alonga line HH′ in FIG. 16;

[0041]FIG. 19 illustrates a plan view of an LCD, according to the fifthembodiment of the present invention; and

[0042]FIG. 20 illustrates a cross-sectional view of the LCD taken alonga line II′ in FIG. 19.

[0043]FIG. 21 is a flowchart showing process steps for structuring aditch that prevents each spacer from entering a transparent region.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] LCDs and their manufacturing methods, according to severalembodiments of the present invention, will be described with referenceto the drawings. These LCDs are structured so as to prevent spacerswithin opaque regions of liquid crystal (e.g., areas of liquid crystalunder a black matrix), which support two substrates facing each otherand allow the liquid crystal to fill the space between them, from movingand entering a transparent region.

First Embodiment

[0045]FIG. 7 is a plan view of an active-matrix LCD, according to thefirst embodiment of the present invention. FIG. 8 is a partialcross-sectional view of the active-matrix LCD taken along a line AA′ inFIG. 7, whereas FIG. 9 is a partial cross-sectional view of theactive-matrix LCD taken along a line BB′ in FIG. 7.

[0046] As shown in these figures, a projection 6 is structured underpart of a black matrix 9 and on the glass substrate 10 where TFTs arefabricated (hereafter, called a TFT substrate), so as to encircle atransparent region. The projection 6 prevents any spacer 17 positionedwithin the light shielded regions of liquid crystal from entering thetransparent region. The projection 6 is positioned in the vicinity of adata line 1, a scanning line 2, or a TFT 3 on/above the TFT substrate10, which have been structured under the black matrix 9 on the undersideof the glass substrate 11.

[0047] As shown in FIG. 8, the projection 6, which is made of a metalpattern, is fabricated at a region overlapped with a part of the blackmatrix 9 and also on a common electrode 4, which is positioned in thevicinity of the data line 1. The material of the projection 6 can bealternatively made of a metal such as Cr, Al, or Mo, or an insulatingmaterial such as SiO₂ or SiN_(x). The formation of the projection 6 canbe done during the fabrication of TFTs on the TFT substrate.Alternatively, the projection 6 can be made of, for example, a resin andformed after the TFTs have been fabricated on the TFT substrate. Analignment layer 15 is then deposited on the surface where the projection6 has been fabricated.

[0048] The distance between the top surface of the alignment layer 15over the projection 6 and the undersurface of the alignment layer 16 onthe opposite facing substrate 11 is shorter than that between the topsurface of the alignment layer 15 on the data line 1 and theundersurface of the alignment layer 16 under the opposite facingsubstrate 11. The width of the projection 6 is equal to or less than thediameter of the spacer 17. Namely, if the diameter of the spacer 17 isequal to 4 μm, the width of the projection 6 is equal to or less than 4μm.

[0049] Besides, as shown in FIG. 9; the distance between the top surfaceof the alignment layer 15 covering the projection 6 and the underside ofthe alignment layer 16 on the opposite facing substrate 11 is shorterthan the distance between the top surface of the alignment layer 15 onthe TFT 3 and the underside of the alignment layer 16 on the oppositefacing substrate 11. The width of the projection 6 is equal to or lessthan the diameter of the spacer 17 in the same form as described above.The projection 6 can be made of a material identical to that of aprotection/insulation film 8 and formed by the following process: First,depositing a thick protection/insulation film 8 on the resultant surfaceincluding the surfaces of the data line 1, an interlayer insulation film7 and a scanning line 3 after TFTs have been fabricated; Secondly,selectively etching off a protection/insulation film 8 so as to leavethe area of the projection 6; Lastly, depositing the alignment layer 15over the entire resultant surface. The projection 6 can be alternativelymade of a material such as a resin and be formed by the followingprocess: First, depositing a protection/insulation film 8 on theresulting surface including the surfaces of data line 1, an interlayerinsulation film 7, and a scanning line 3 after TFTs have beenfabricated; Secondly, depositing any one of the materials for theprojection 6 as described above on top of the protection/insulation film8; Thirdly, selectively etching of the deposited material so as to leavethe area of the projection 6; Lastly, depositing the alignment layer 15all over the resultant surface. Afterwards, a plurality of spacers aredistributed throughout the resultant surface. The fabricated oppositefacing substrate, as illustrated in the upper area of FIGS. 8 and 9, isthen fixed on top of the multiple spacers, and liquid crystal 18 isinjected into the space between the two fabricated substrates.

[0050] The difference between the said distance from the top surface ofthe alignment layer 15 on the TFT 3, the data line 1 and the scanningline 2, to the undersurface of the alignment layer 16 on the oppositefacing substrate 11, and the distance from the top surface of thealignment layer 15 on top of the projection 6 to the undersurface of thealignment layer 16 on the opposite facing substrate 11 is equal to orlonger than approximately 1% the length of the diameter of the spacer17, and it is preferable that it be equal to or longer thanapproximately 2%. In other words, the height of each projection 6 isequal to or longer than approximately 1% the length of the diameter ofthe spacer 17, and it is preferable that it be equal to or longer thanapproximately 2%. This prevents each spacer 17 positioned within theopaque regions (i.e., under the black matrix 9) from climbing over theprojection 6 and then entering a transparent region of liquid crystalmolecules.

[0051] In summary, according to the first embodiment of the presentinvention, the projection 6 is structured on the TFT substrate 10, withthe distance between the top surface of the alignment layer 15 coveringthe projection 6 and the underside of the alignment layer 16 on theopposite facing substrate 11 being shorter than the distance between thetop surface of the alignment layer 15 on the data line 1, the scanningline 2 and the TFT 3, and the undersurface of the alignment layer 16 onthe opposite facing substrate 11.

[0052] Due to this structure, even if a certain pressure or impacthappens to be applied onto the LCD panel, it is difficult for any spacer17, which is positioned within the opaque regions or under the blackmatrix 9, to climb over the projection 6, and then enter a transparentregion; therefore, the leakage of light decreases, and the contrast isimproved. Also, a possible unevenness in display quality due to theareas of the leakage of light being unevenly distributed is decreased.Furthermore, the panel becomes more durable against certain vibrationsand impacts: Even if certain vibrations and impacts happen to hit thefabricated active-matrix LCD after it has been inspected, they cannotdamage it. As a result, high display quality is provided.

[0053] Incidentally, FIG. 7 illustrates a continuously extendingprojection 6 positioned along the black matrix extensions. However, thepresent invention is not limited to this. Alternatively, the projection6 can be made up of multiple, intermittent pieces positioned along theextensions of the black matrix 9. In other words, a broken line ofprojections can be formed on the inner-most surface of the TFT substrate10 so as to encircle the transparent regions. The length of each gap inthe broken line of projections is shorter than the diameter of thespacer 17.

Second Embodiment

[0054] Next, an LCD, according to the second embodiment of the presentinvention, will be described while referencing FIGS. 10 to 12. FIG. 10illustrates a plan view of the LCD of the second embodiment. FIG. 11illustrates a cross-sectional view of the LCD taken along a line CC′ inFIG. 10; whereas FIG. 12 illustrates a cross-sectional view of the LCDtaken along a line DD′ in FIG. 10.

[0055] In the LCD of the second embodiment, as shown in FIGS. 10 to 12,a projection 19 is structured on the undersurface of an opposite facingsubstrate 11 under part of a black matrix 9, instead of on the topsurface on a TFT substrate 10, as in the first embodiment. During thefabrication of the opposite facing substrate 11, the projection 19 isstructured during the formation of the first colored layer 12 and anover-coating film 14. The projection 19 is made of a material identicalto that of a over-coating film 14, and can be formed by the followingprocess: First, depositing a thick over-coating film on the underside ofthe colored layers including the first and the second colored layers 12and 13, which have been deposited on the undersides of the black matrix9 and the opposite facing glass substrate 11; Secondly, selectivelyetching off the deposited film so as to leave the area of the projection19; Lastly, depositing the alignment layer 16 over the entire resultantsurface. The projection 19 can be alternatively formed by the followingprocess: First, depositing an over-coating film 14 on the underside ofthe colored layers including the first and the second colored layers 12and 13, which have been deposited on the undersides of the black matrix9 and the opposite facing glass substrate 11; Secondly, depositing amaterial for the projection 19 on top of the deposited over-coating film14; Thirdly, selectively etching off the deposited material so as toleave the area of the projection 19; Lastly, depositing the alignmentlayer 16 over the entire resultant surface of both the over-coating film14 and the projection 19.

[0056] Also, the projection 19 and the over-coating film 14, as shown inFIG. 11, are simultaneously formed under the black matrix 9 on theopposite facing substrate 11. The distance between the undersurface ofthe alignment layer 16 on top of the projection 19 and the top surfaceof the alignment layer 15 on the TFT substrate 10 is shorter than thatbetween the top surface of the alignment layer 15 on the data line 1 andthe undersurface of the alignment layer 16 on the opposite facingsubstrate 11. The width of the projection 19 is equal to or less thanthe diameter of the spacer 17. That is, if the diameter of the spacer 17is equal to 4 μm, the width of the projection 19 is accordingly equal toor less than 4am.

[0057] As shown in FIG. 12, the projection 19 is structured under partof the black matrix 9 in the vicinity horizontal to the scanning line 2and the TFT 3. The distance between the undersurface of the alignmentlayer 16 on the underside of the projection 19 and the top surface ofthe alignment layer 15 on the TFT substrate 10 is shorter than thatbetween the top surface of the alignment layer 15 on both the scanningline 2 and TFT 3, and the undersurface of the alignment layer 16 on theopposite facing substrate 11. The width of the projection 19 is equal toor less than the diameter of the spacer 17, as in the same format asdescribed above.

[0058] The difference between the distance from the top surface of thealignment layer 15 on the data line 1, the scanning line 2, and the TFT3, to the undersurface of the alignment layer 16 at the opposite facingsubstrate 11, and the distance from the undersurface of the alignmentlayer 16 on the underside of the projection 19 to the top surface of thealignment layer 15 at the TFT substrate 10 is, as is in the same formatas the first embodiment, equal to or longer than approximately 1% thelength of the diameter of the spacer 17, and it is preferable that it beequal to or longer than approximately 2%. In other words, the height ofeach projection 19 is equal to or longer than approximately 1% thelength of the diameter of the spacer 17, and it is preferable that it beequal to or longer than approximately 2%.

[0059] In summary, according to the second embodiment of the presentinvention, the projection 19 is structured on the opposite facing glasssubstrate 11 with the distance between the undersurface of the alignmentlayer 16 on the underside of the projection 19 and the top surface ofthe alignment layer 15 on the TFT substrate 10 being shorter than thatbetween the top surface of the alignment layer 15 on the data line 1,the scanning line 2, and the TFT 3, and the undersurface of thealignment layer 16 on the opposite facing substrate 11.

[0060] Due to this format, even if a certain pressure or an impacthappens to hit the LCD panel of the second embodiment, it is difficultfor any spacer 17 positioned within the opaque regions (i.e., under theblack matrix or on either the data line 1, the scanning line 2, or theTFT 3) to enter a transparent region. This prevents a possible increasein leakage of light caused by the entry of each spacer from occurring.As a result, the leakage of light decreases, and the contrast isimproved. Also, the uneven display resulting from areas of the leakageof light being unevenly distributed is reduced. Furthermore, the panelbecomes more durable against certain vibrations and impacts: Even ifcertain vibrations and impacts happen to hit the fabricated,active-matrix LCD after it has been inspected, they cannot damage it.

[0061] Incidentally, FIG. 10 illustrates a continuously extendingprojection 19 positioned along the black matrix extensions. However, thepresent invention is not limited to this. Alternatively, the projection19 can be made up of multiple, intermittent pieces positioned along theextensions of the black matrix 9. In other words, a broken line ofprojections can be formed on the inner-most surface of the TFT substrate11 so as to encircle the transparent regions. The length of each gap inthe broken line of projections is shorter than the diameter of thespacer 17.

Third Embodiment

[0062] Next, an LCD, according to the third embodiment of the presentinvention, will be described while referencing FIGS. 13 to 15. In brief,the LCD of the third embodiment is attained by combining the structuresof the first and the second embodiment together. FIG. 13 illustrates aplan view of the LCD of the third embodiment. FIG. 14 illustrates across-sectional view of the LCD taken along a line EE′ in FIG. 13;whereas FIG. 15 illustrates a cross-sectional view of the LCD takenalong a line FF′ in FIG. 13.

[0063] According to the LCD of the third embodiment, as shown in FIGS.14 and 15, two independent projections 6 and 19 are structured on therespective TFT glass substrate 10 and opposite facing glass substrate11. The fabrication processes for the two projections 6 and 19 areidentical to those in the first and second embodiment.

[0064] As shown in FIG. 14, the projection 6, which is made of metalpattern, is structured under part of the black matrix 9, and on thecommon electrode 4 on top of the TFT substrate 10. On the other hand,the projection 19 is structured to be part of the over-coating film 14on the opposite facing substrate 11, under the same part of the blackmatrix 9. The projections 6 and 19 on the respective TFT substrate 10and opposite facing substrate 11 face each other. The distance betweenthe top surfaces of the alignment layers 15 and 16 on top of therespective projections 6 and 19 is shorter than the distance between thetop surface of the alignment layer 15 on the data line 1 and theundersurface of the alignment layer 16 on the opposite facing substrate11.

[0065] With this format, the heights of the respective projections 6 and19 can be half of those of the respective first and second embodiments.The widths of the respective projections 6 and 19 are equal to or lessthan the diameter of the spacer 17 in the same format as the first andthe second embodiment.

[0066] Incidentally, the present invention is not limited to thearrangement of the projections 6 and 19 facing each other and beingpositioned under a part of the black matrix 9. In other words, each ofthe projections 6 on the TFT glass substrate 10 can be positioned farfrom each of the projections 19 on the facing glass substrate 11 as longas they are positioned under part of the black matrix 9, so as toprevent each spacer 17 positioned under the black matrix 9 from climbingover and entering an optical transparent region. In this case, thedistance between the top surface of the alignment layer 15 on top ofeach projection 6 and the undersurface of the alignment layer 16 on thefacing glass substrate 11, and the distance between the undersurface ofthe alignment layer 16 on top of each projection 19 and the top surfaceof the alignment layer 15 on the TFT glass substrate 10 should both beshorter than the distance between the top surface of the alignment layer15 on the data line 1 and the undersurface of the alignment layer 16 onthe facing glass substrate 11.

[0067] Due to the aforementioned arrangement of the projections 6 and 19facing each other, the number of the projections is doubled the numberof those in each of the first and the second embodiments. This preventseach spacer positioned under the black matrix 9 from climbing over theprojections and entering a transparent region.

[0068] Next, other projections 6 and 19 positioned near a TFT 3 will bedescribed while referencing FIG. 15. As shown in FIG. 15, the projection6, which is made of a metal pattern, is structured under part of theblack matrix 9 and on the common electrode 4 formed near the scanningline 2 and TFT 3 on the TFT glass substrate 10. On the other hand, theprojection 19, which is made of the same material as that of theover-coating film 14, is structured under part of the black matrix 9 onthe undersurface of the opposite facing glass substrate 11, and is alsopositioned, in the horizontal direction, near the data line 1.

[0069] The projections 6 and 19 on the respective TFT glass substrate 10and opposite facing substrate 11 face each other. The distance betweenthe alignment layers 15 and 16 on the tops of the respective projections6 and 19 is shorter than the distance between the top surface of thealignment layer 15 on both the scanning line 2 and the TFT 3, and theundersurface of the alignment layer 16 on the opposite facing glasssubstrate 11. This allows the heights of the respective projections 6and 19 to be half the length of those of the first and the secondembodiment. The widths of the respective projections 6 and 19 are equalto or less than the diameter of the spacer 17 in the same format as thefirst and the second embodiment.

[0070] Incidentally, up to this point, it has been explained that theprojections 6 and 19 in FIG. 15 face each other. However, the presentinvention is not limited to this. Alternatively, each projection 6 canbe positioned not facing each projection 19. In this case, the distancebetween the top surface of the alignment layer 15 on top of eachprojection 6 and the undersurface of the alignment layer 16 on thefacing glass substrate 11 and the distance between the undersurface ofthe alignment layer 16 on top of each projection 19 and the top surfaceof the alignment layer 15 on the TFT glass substrate 10 should be bothshorter than the distance between the top surface of the alignment layer15 on both the scanning line 2 and TFT 3, and the undersurface of thealignment layer 16 on the facing glass substrate 1-1.

[0071] Due the structure of the projections 6 and 19 on the respectiveTFT glass substrate 10 and facing glass substrate 11, the total numberof projections 6 and 19 is each double those of the first and the secondembodiment. This allows a surer prevention of each spacer 17 under theblack matrix 9 from entering an optical transparent region.

[0072] The difference between the distance from the top surface of thealignment layer 15 on the data line 1, the scanning line 2, and the TFT3, to the undersurface of the alignment layer 16 on the opposite facingsubstrate 11, and the distance from the undersurface of the alignmentlayer 16 on the underside of the projection 19 to the top surface of thealignment layer 15 on the TFT substrate 10 is, as is in the same form asthe first embodiment, equal to or longer than approximately 1% thelength of the diameter of the spacer 17, and it is preferable that it beequal to or longer than approximately 2%. Also, the difference betweenthe former distance and the distance between the top surface of thealignment layer 15 on top of the projection 6 and the undersurface ofthe alignment layer 16 at the opposite facing substrate 11 is equal toor longer than approximately 1% the length of the diameter of the spacer17, and it is preferable that it be equal to or longer thanapproximately 2%.

[0073] Due to this format described above, even if a certain pressure orimpulse happens to be applied onto the LCD panel of the thirdembodiment, each spacer 17 positioned under the black matrix and oneither the data line 1, the scanning line 2, or the TFT 3, is preventedfrom moving, climbing over, and entering a transparent region. Thisprevents a possible increase in the total amount of leakage of light dueto the entry of each spacer 17. As a result, the leakage of lightdecreases, and the contrast is improved. Also, the uneven displayresulting from areas of the leakage of light being unevenly distributedis reduced. These advantages allow the provision of an active-matrix LCDwith high reliability.

[0074] Incidentally, FIG. 13 illustrates continuously extendingprojections 6 and 19 positioned along the black matrix extensions.However, the present invention is not limited to this. Alternatively,the projections 6 and 19 can be made up of multiple, intermittent piecespositioned along the extensions of the black matrix 9.

Fourth Embodiment

[0075] Next, an LCD, according to the fourth embodiment of the presentinvention, will be described while referencing FIGS. 16 to 18. In brief,the LCD of the fourth embodiment is attained by structuring differenttypes of projections on the TFT glass substrate 10 from the projections6 and 19 in the first to the third embodiments. FIG. 16 illustrates aplan view of the LCD of the fourth embodiment. FIG. 17 illustrates across-sectional view of the LCD taken along a line GG′ in FIG. 16;whereas FIG. 18 illustrates a cross-sectional view of the LCD takenalong a line HH′ in FIG. 16.

[0076] As shown in FIGS. 17 and 18, each of the aforementionedprojections or bumps are structured by positioning a common electrode 4on top of the TFT glass substrate 10. This causes the distance betweenthe top surface of each bump caused by the common electrode 4, and theunderside of the opposite facing glass substrate 11 to be shorter thanthe distance between the top surface of the alignment layer 15 on thedata line 1, the scanning line 2, and the TFT 3, and the undersurface ofthe alignment layer 16 of the opposite facing glass substrate 11.

[0077] The difference between the distance from the top surface of thealignment layer 15 on the data line 1, the scanning line 2 and the TFT3, to the undersurface of the alignment layer 16 of the facing glasssubstrate 11, and the distance from the top surface of the bump on thecommon electrode 4 to the undersurface of the alignment layer 16 of theopposite facing glass substrate 11 is equal to or longer thanapproximately 1% the length of the diameter of the spacer 17, and it ispreferable that it be equal to or longer than approximately 2%. In otherwords, the height of each bump is equal to or longer than approximately1% the length of the diameter of the spacer 17, and it is preferablethat it be equal to or longer than approximately 2%. This allows theprevention of the spacer 17 from moving and entering an opticaltransparent region. In addition, each bump can be formed more easily bystructuring the common electrode 4 on the TFT substrate 10 thanstructuring the projections 6 and 19 according to the first throughthird embodiments. Accordingly, each bump can be fabricated by shortenedprocess steps.

[0078] Due to the form of the LCD of the fourth embodiment, even if acertain pressure or impulse happens to be applied onto the LCD panel,each spacer 17 under the black matrix 9 and on either the data line 1,the scanning line 2, or the TFT 3, is prevented from moving and enteringa transparent region. This prevents a possible increase in a totalleakage of light due to each spacer 17. As a result, the displayingcontrast is improved. Also, the uneven display resulting from areas ofleakage of light being unevenly distributed is reduced. These advantagesallow the provision of an active-matrix LCD with high reliability.

Fifth Embodiment

[0079] Next, an LCD, according to the fifth embodiment of the presentinvention, will be described while referencing FIGS. 19 to 20. In thisembodiment, in place of forming each projection or bump, which preventseach spacer 17 within opaque regions (i.e., under the black matrix 9)from entering an optical transparent region, a ditch is formed on theinner surface of either the TFT glass substrate 10 or the facing glasssubstrate 11, so as to confine each spacer 17 within it, as shown inFIG. 20. FIG. 19 illustrates a plan view of the LCD of the fifthembodiment; whereas FIG. 20 illustrates a cross-sectional view of theLCD taken along a line II′ in FIG. 19.

[0080] In FIG. 20, the ditch where each spacer 17 is confined is formedon the inner surface of the TFT substrate 10 under the black matrix 9.As shown in the flowchart in FIG. 21, the ditch is formed by thefollowing process steps: First, a protection/insulation film 8 isdeposited over the surface of both the data line 1 and common electrode4, which have been formed on top of the TFT glass substrate 10 (stepS1); Secondly, an area of the deposited protection/insulation film 8under the black matrix 9, where at least one spacer 17 is laterpositioned, is etched off so as to form a ditch (step S2); Thirdly,interlayer insulation film 7 is deposited onto the resultant surface(step S3); Fourthly, an alignment layer 15 is deposited onto theresultant surface (step S4); Fifthly, a spacer 17 is placed within theresultant ditch (step S5); Lastly, the opposite facing substrate 11 withthe black matrix 9, colored layers 12 and 13, over-coating film 14, andalignment layer 16, which have been arranged in the format as shown inFIG. 20, is fixed onto the spacers 17 so as to face the TFT glasssubstrate 10. With this structure, each spacer 17 in the ditch cannot goover the wall 22 of the ditch, thus being confined within it.

[0081] The distance between the top surface of the alignment layer 15 onthe common electrode 4 and the inner surface of the alignment layer 16on the opposite facing glass substrate 11 is shorter than the distancebetween the top surface of the alignment layer 15 on the signal 1 andthe inner surface of the alignment layer 16 on the facing glasssubstrate 11, as shown in FIG. 20. The difference between the formerdistance and the latter distance is equal to or longer thanapproximately 1% the length of the diameter of the spacer 17, and it ispreferable that it be equal to or longer than approximately 2%. Thisallows the prevention of the spacer 17 from moving and entering anoptical transparent region. As a result, even if a certain pressure orimpulse happens to be applied onto the LCD, each spacer 17 within the onditch is prevented from moving and entering a transparent region. Thisprevents an increase in total leakage of light around each spacer 17. Asa result, the uneven display resulting from areas of the leakage oflight being unevenly distributed is reduced. These advantages allow theprovision of an active-matrix LCD with high reliability and highdisplaying quality.

[0082] In the above description, the case where the ditch is formed atthe TFT glass substrate 10 is explained. However, the present inventionis not limited to this. A ditch that confines each spacer 17 within itcan be naturally formed on the opposite facing glass substrate 11.

[0083] Furthermore, in the above description, the case where the presentinvention is used for a lateral electric field-type/TFT active matrixLCD is explained. However, the present invention is not limited to this.The structure with the projections, the bumps, and the ditches asdescribed above, according to the present invention, can also benaturally used for the simple matrix TN(twisted nematic)- and STN(supertwisted nematic)-type LCD, the ferroelectric LCD, the polymer disbursedLCD, etc. The lateral electric field-type active matrix LCD, inparticular, often uses the normally black system (i.e., black isdisplayed while no voltage is applied), and may easily develop leakageof light due to the disarray in liquid crystal molecule orientationaround each spacer. This problem of leakage of light can be prevented byutilizing the aforementioned structures according to the presentinvention.

[0084] LCDs, and their manufacturing methods, according to the presentinvention, have been described in connection with several preferredembodiments. It is to be understood that the subject matter encompassedby the present invention is not limited to that specified embodiment. Onthe contrary, it is intended to include all alternatives, modifications,and equivalents as can be included within the spirit and scope of thefollowing claims.

1-6. (Canceled).
 7. A liquid crystal display (LCD), comprising at leastone spacer which is positioned under an opaque region and at least oneprojection which is formed under said opaque region, and on at least oneof the inner-most surfaces of a first and a second substrate, whereinsaid projection is formed by structuring a common electrode. 8-14.(Canceled).
 15. A method of manufacturing an LCD, comprising: depositingan insulation film at a transparent substrate; etching off an area ofsaid insulation film under an opaque region so as to form a ditch; anddepositing an alignment layer on the resultant surface of saidinsulating film.
 16. The method, according to claim 15, wherein the wallof said ditch is high enough to confine a spacer positioned in saidditch.
 17. The method, according to claim 15, wherein said depositing ofsaid insulation film is performed on the surface resulting fromfabricating thin film transistors on said transparent substrate.